<?php
namespace think;
class Model
{
    /**
     * 指定AND查询条件.
     *
     * @param mixed $field     查询字段
     * @param mixed $op        查询表达式
     * @param mixed $condition 查询条件
     *
     * @return $this
     */
    public static function where($field, $op = null, $condition = null){}
}

// class Db{
//     public static function where($field, $op = null, $condition = null){}
// }